1. Field of the Invention
The present invention relates to a tape cartridge.
2. Description of Related Art
FIG. 9 is a conceptual plan view showing an internal structure of a conventional tape cartridge in which a single reel having an upper flange and a lower flange is housed rotatably in a case. FIG. 10 is a sectional view showing the tape cartridge shown in FIG. 9, taken along a line F-F. It should be noted that, in FIG. 9, a second container 101b of a case 101 in FIG. 10 is omitted. Further, although a first container 101a is disposed below the second container 101b in FIG. 10, the first container 101a is disposed above the second container 101b in ordinary use.
A reel 102 is pressed and biased upward in FIG. 10 by a compression coil spring 128 acting via a shaft 127. However, in a running state, the reel 102 is raised toward the first container 101a by a drive shaft 108 of a drive and rotates at a position slightly away from the second container 101b. When the reel 102 rotates, a tape 103 is wound around the reel 102 or fed out from the reel 102. A metal leader 106 is fixed to the fed-out end of the tape, and when the tape cartridge is loaded in the drive, the leader 106 is grasped by a coupler of the drive. In this way, the tape 103 is supplied to a drive system of the drive. In FIG. 9, numeral 104 denotes a guide roller of the drive system of the drive.
Now, in the conventional tape cartridge described above, any of the following structures (1) to (3), for example, has been adopted for smoother tape winding:    (1) the structure in which through holes or grooves are provided in part of the flanges of the reel in order to release the air that is entrained in the tape when winding the tape (in the following, also referred to as “the entrained air”) (see JP 2001-118355 A, for example);    (2) the structure in which the gap between the upper and lower flanges of the reel is reduced so as to decrease the clearance between the tape and each of the flanges, thereby restricting the position of the tape with the flanges; and    (3) the structure in which the case is provided with a guide roller so as to wind the tape around the reel at a predetermined angle (see JP 2003-45145 A, for example).
However, in the conventional cartridge, intrinsic irregularities of the tape, for example, uneven thickness, curve, etc. of the tape have caused the instability of a running position of the tape, resulting in uneven tape winding. Therefore, the above-described through holes or groves for releasing the entrained air effectively when the tape and the flanges are in close contact with each other have not functioned sufficiently. In the case where the gap between the upper and lower flanges is reduced, vertical variation in the running position of the tape may cause a tape edge to contact one of the flanges, leading to the problem of the tap being damaged. In the case where the guide roller or the like is used to restrict the running position, etc. of the tape, since the running stability of the tape improves to some degree, the smoothness in tape winding also improves. However, the degree of improvement has not been sufficient for the following reason.
The reel 102 is movable vertically or horizontally to a certain degree. On the other hand, since the guide roller is fixed to a predetermined position of the case, it cannot follow the inclination, horizontal displacement, vertical movement or the like of the reel. Thus, the running position, etc. of the tape cannot be restricted stably using the guide roller. In fact, it has been known that the engagement between a driving gear provided to the drive shaft of the drive and its corresponding engaging gear of the reel varies every time, so that the reel may be inclined or displaced in an arbitrary direction in some cases.
With the foregoing in mind, the present invention provides a tape cartridge with smoother tape winding by achieving stabilized running of the tape without being affected considerably by the inclination, positional displacement, etc. of the reel.